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Showing results for tags 'fuel supply'.
Hi, I've been hunting and chasing my tail to get some kind of throttle response from my wrangler above 45 MPH. I know these are not very powerful to start but I feel like what I'm experiencing is abnormal. Anywhere above about 45MPH when throttle is given There is little or no response from the engine. I have gone through the tuning and troubleshooting, replaced numerous things and adjusted what is able to be adjusted to the best of my understanding. Most recently I put a new cylinder head on due to a cracked web between valves on cylinder 4. I was so sure this was going to solve my issue considering the cylinder was down to 70psi compression. Though the engine runs smoother and quieter now it still is lagging at higher speed. 5th gear is pretty much useless unless going down hill. I have access to a modis scan tool so I can see ecu data. What is bothering me at this time is the engine rpm's are reading about 400 rpm's lower than my tach. Idling around 575 rpm's according to the scan tool data but reading around 1000 on the tach. In my opinion it feels like it is closer to the 1000 rpm range but I don't have a way to check it at this moment. My question is where does the ECU get the engine speed? is it from the ICM or the CPS? If its the cps can the cps fail in a way that it still reads but reads low? I may be barking up the wrong tree and I likely am. but right now I'm trying anything i can think of. Any other suspected areas to check? Any scan tool data that would be more important than others? Any suggestion is welcome. Thanks Dan
Hello to All.... I wish to thank all the members and especially you Mr. Ludell for all the time spent on our endless problems.... I have reviewed all the posts that might pertain to my problem and do not wish to ask a question that can be easily answered by simple review... My YJ has had an.. "on again / off again" problem that may not be related to this exact problem but it just seems to have never been 100 % or maybe even 80%... The current problem started on an outing in the woods ..drove fine climbing, downhill and 4wd.. coming back the engine began to act like it was starving for fuel..the harder you press on the gas the more it chocked out...would idle fine..no power.. So... I took it to mean a faulty pump and ordered same...pulled tank ..found sock off the pump..Problem solved ??..decided since I have a new one might as well drop it in.. "nice to have a trail spare anyway".. replaced tank with new filter... went to fire it up ...no start..no apparent fuel at the TBI....Now it wont run at all... So... check electrical to pump ..fine..check lines..fine.. Ordered a Pressure gauge...slap it on the TBI access port ..No pressure.....Check pressure before the TBI... jumps to 50 psi...way to much..?? checked inline with " T " Key on 25 psi.. Start..jumps to 50 psi..no apparent fuel returning to tank.. SO.... rebuild the TBI... bad regulator..Maybe...clean, replace TPS , new injector, and filters while its apart... " Nice to have trail spares anyway" reassemble...try to start ...no fuel.... So....Back to ZERO.... No fuel getting past the Regulator... Remove TBI..reinspect , reassemble..try to start...no fuel Also the CPS..MAT sensors replaced during the last session...Of unknown problems..."Nice to have trail spares anyway" When fuel is manually poured in the carb. she fires right up and I can keep it running if i drizzle it in.. So... it runs if i can figure out how to get my wife under the hood with a squeeze bottle while I drive....Could work...Maybe.. Make a great hood ornament...Should switch that around encase she reads this..She Drives....ya sounds better... The questions are.....will the pressure spike to 50 psi if there is no return to tank..? Is 50 psi just way to much ..? Will to much pressure cause the regulator to shut down so to speak..? Is it possible the spring in the regulator is bad ,The kit did not have a new spring...Seems a weak spring would allow to much fuel...did try to adjust with set screw...no Fuel...? The TBI is clean no blockage in ports...so what could be stopping the flow... Other than the regulator... ? "Did I just answer my own question..Maybe" Why are my troubles worse now after the repairs..At least it ran at idle before? Your Attention , Patience and experience with this matter will earn you my admiration and a box of Girl Scout cookies...of your choice Jamie